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Chapter 14. Construct, Deliver, and Maintain Systems Projects. Accounting Information Systems, 5 th edition James A. Hall. SDLC major phases. Systems strategy Project initiation In-house development Commercial packages Maintenance & support. Chapter 13. Chapter 14. 5 major phases.

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chapter 14

Chapter 14

Construct, Deliver, and Maintain Systems Projects

Accounting Information Systems,

5th edition

James A. Hall

sdlc major phases
SDLC major phases
  • Systems strategy
  • Project initiation
  • In-house development
  • Commercial packages
  • Maintenance & support

Chapter 13

Chapter 14

5 major phases

slide3

Systems Development Life Cycle

Business Needs and

Strategy

Legacy Situation

Business Requirements

1. Systems Strategy - Assessment - Develop Strategic Plan

Ch13

Feedback:User requests for New Systems

System Interfaces, Architecture and User Requirements

High Priority Proposals undergo Additional Study and Development

2. Project Initiation

- Feasibility Study - Analysis

- Conceptual Design

- Cost/Benefit Analysis

Ch13

Feedback:User requests for System Improvements and Support

Selected System Proposals go forward for Detailed Design

3. In-house Development - Construct- Deliver

4. Commercial Packages - Configure - Test - Roll-out

Ch14

Ch14

New and Revised Systems Enter into Production

5. Maintenance & Support - User help desk

- Configuration Management

- Risk Management & Security

Ch14

overview of phases 3 4 and 5
Overview of Phases 3, 4 and 5
  • Phase 3 - In-House Development
    • appropriate when organizations have unique information needs
    • steps include:
      • analyzing user needs
      • designing processes and databases
      • creating user views
      • programming the applications
      • testing and implementing the completed system
overview of phases 3 4 and 51
Overview of Phases 3, 4 and 5
  • Phase 4 - Commercial Packages
    • when acceptable, most organizations will seek commercial software package
    • advantages:
      • lower initial cost
      • shorter implementation time
      • better controls
      • rigorous testing by the vendor
    • risks:
      • must adequately meet end users’ needs
      • must be compatible with existing systems
overview of phases 3 4 and 52
Overview of Phases 3, 4 and 5
  • Phase 5 - Maintenance and Support
    • acquiring and implementing the latest software versions of commercial packages
    • making in-house modifications to existing systems to accommodate changing user needs
    • may be relatively trivial, such as modifying an application to produce a new report, or more extensive, such as programming new functionality into a system
3 problems that account for most system failures
3 problems that account for most system failures…
  • Poorly specified systems requirements

communication problems

time pressures

  • Lack of user involvement

in systems development/selection

3. Ineffective development techniques

(for internally developed systems)

systems

developer

end

user

prototyping
Prototyping
  • Provides preliminary working version of the system
  • Built quickly and relatively inexpensively with the intention it will be modified
  • End users work with the prototype and make suggestions for changes.
    • A better understanding of the true requirements of the system is achieved.
computer aided software engineering case
Computer-Aided Software Engineering (CASE)
  • CASE technology uses computer systems to build computer systems.
  • CASE tools are commercial software products consisting of highly integrated applications that support a wide range of SDLC activities.
pert charts
PERT charts
  • Used to show relationship among key activities of a systems project
  • Probably used more for in-house development (than commercial software acquisition)
slide12

Project Evaluation and Review Technique (PERT)

Deliver Phase

Construct Phase

D

G

A-D 3 Weeks

Purchase Equipment

Install and Test Equipment

D-F 2 Weeks

Prepare Documentation

F-G 3 Weeks

G-I 3 Weeks

Train Personnel

A-B 4 Weeks

B-F 5 Weeks

F-I 3 Weeks

Design Data Model

Create Data Structures

Convert Data Files

A

B

F

I

Test Programs

H-I 4 Weeks

E-F 3 Weeks

Design Process

Cut Over to New System

A-C 4 Weeks

F-H 4 Weeks

C-E 5 Weeks

Test System

Code Programs

C

E

H

PERT charts show the relationship among key activities that constitute the construct and delivery process.

structured design approach
Structured Design Approach
  • A disciplined way of designing systems from the top down
  • Starts with the “big picture” of the proposed system and gradually decomposes it into greater detail so that it may be fully understood
  • Utilizes data flow diagrams (DFDs) and structure diagrams (not necessary to study DFDs)
systems design
Systems Design
  • Follows a logical sequence of events:
    • model the business process and design conceptual views
    • design normalized database tables
    • design physical user views (output and input views)
    • develop process modules
    • specify system controls
    • perform system walkthroughs
data modeling
Data Modeling
  • Formalizes data requirements of the business process as conceptual model
  • Entity-relationship diagram (ERD)
    • primary tool for data modeling
    • used to depict the entities or data objects in system
  • Each entity in ER diagram is a candidate for a conceptual user view that must be supported by database.
normalization
Normalization
  • User views in data modelmust be supported by normalized database tables.
  • Normalization of database tables:
    • A process of organizing tables so that entities are represented unambiguously
    • Eliminates data redundancies and associated anomalies
    • Depends on the extent that the data requirements of all users have been properly specified in the data model
    • The resulting databases will support multiple user views
  • More detail in chapter 9 about data normalization
physical user views output views
Physical User Views: Output Views
  • Output is the information produced by the system to support user tasks and decisions.
  • Output attributes:

-relevant

-summarization

-except orientation

-timely-accurate-complete-concise

designing hard copy input
Designing Hard Copy Input
  • Items to Consider:
    • How will the document be handled?
    • How long will the form be stored and in what type of environment?
    • How many copies are required?
    • What size form is necessary?
      • Non-standard form can cause printing and storage problems.
designing system controls
Designing System Controls
  • The last step in the detailed design phase
  • Need to consider:
    • computer processing controls
    • data base controls
    • manual controls over input to and output from the system
    • operational environment controls
  • Allows the design team to review, modify, and evaluate controls with a system-wide perspective that did not exist when each module was being designed independently
systems walkthrough
Systems Walkthrough
  • Usually performed by the development team
    • Ensure that design is free from conceptual errors that could become programmed into the final system
  • Some firms use a quality assurance (QA) group to perform this task.
    • An independent group of programmers, analysts, users, and internal auditors
slide21

M

T

E

S

Y

S

The Delivery

delivering a system
Delivering a system
  • Appropriate for commercial software or in-house development
    • Test entire system
    • Document the system
      • Designer/Programmer documentation (in-house)
      • Operator documentation (more centralized than distributed)
      • User documentation
      • Accountant/Auditor documentation
conversion of databases
Conversion of databases
  • Appropriate for commercial software or in-house development
    • Transfer of data from old system to new system
    • Validate data before conversion
    • Reconcile data after conversion
    • Keep backup copies of old data!
converting to new system
Converting to New System

Three approaches:

  • Cold turkey cutover (“Big Bang”) - firm switches to new system on particular day and simultaneously terminates old system. Riskiest approach.
  • Phased cutover - modules are implemented in piecemeal fashion. Risk of devastating failure can be reduced.
  • Parallel cutover - old system and new system are run simultaneously. Safest, yet costliest, approach.
role of accountants in construct deliver phases
Role of Accountants in Construct & Deliver Phases
  • Accountant should:
    • Provide technical expertise re: GAAP, GAAS, SEC regulations, SoX, IRS code.
    • Specify documentation standards
    • Verify control adequacy
4 commercial software
4. Commercial Software
  • Four factors have stimulated growth of commercial software:
    • relatively low cost
    • prevalence of industry-specific vendors
    • growing demand by small businesses
    • trend of organizational downsizing and distributed data processing
types of commercial software
Types of Commercial Software
  • Turnkey systems:completely finished and tested systems -- ready for implementation.
  • Backbone systems: provide basic system structure on which to build.
  • Vendor-supportedsystems:custom-developed and maintained by vendor for customer.
  • ERP systems are difficult to classify because they have characteristics of all of the above.
commercial software
Commercial Software
  • Advantages
    • Implementation time
    • Cost
    • Reliability
  • Disadvantages
    • Dependence on vendors
    • Need for customized systems
    • Maintenance
steps in choosing a commercial package
Steps in Choosing a Commercial Package
  • Needs analysis
  • Send out Request for Proposals(RFP) to prospective vendors to serve as comparative basis for initial screening.
  • Gather facts about each vendor’s system using multiple sources and techniques.
  • Analyze findings and make final selection.
maintenance and support
Maintenance and Support
  • Approximately 80% of the life and costs of SDLC
  • Can be outsourced or done in-house
  • End user support is a critical aspect of maintenance that can be facilitated by:
    • knowledge management - method for gathering, organizing, refining, and disseminating user input
    • group memory - method for collecting user input for maintenance and support